chap, xv.] THE WRIST AND HAND. 239 



grooves that may be seen to separate the elevations 

 correspond to those slips. 



Of the many creases in the skin of the palm 

 three require especial notice. The first starts 

 at the wrist, between the thenar and hypothenar 

 eminences, and marking off the former eminence 

 from the palm ends at the outer border of the 

 hand at the base of the index finger. The second 

 fold is slightly marked. It starts from the outer 

 border of the hand, where the first fold ends, It runs 

 obliquely inwards across the palm with a marked 

 inclination towards the wrist, and ends at the outer 

 limit of the hypothenar eminence. The third, lowest, 

 and best-marked of the folds starts from the little 

 elevation opposite the cleft between the index and 

 middle fingers, and runs nearly transversely to the 

 ulnar border of the hand, crossing the hypothenar 

 eminence at the upper end of its lower fourth. An 

 unimportant crease running obliquely from the third 

 to the second fold give's to these markings the outline 

 of the letter M. The first fold is produced by the 

 opposition of the thumb, the second mainly by the 

 bending simultaneously of the metacarpo-phalangeal 

 joints of the first and second fingers, and the third by 

 the flexion of the three inner fingers. The second 

 fold, as it crosses the third metacarpal bone, about 

 corresponds to the lowest point of the superficial 

 palmar arch. The third fold crosses the necks of the 

 metacarpal bones, and indicates pretty nearly the 

 upper limits of the synovial sheaths for the flexor 

 tendons of the three outer fingers. A little way 

 below this fold the palmar fascia breaks up into its 

 four slips, and midway between the fold and the webs 

 of the fingers lie the metacarpo-phalangeal joints. 

 Of the transverse folds across the fronts of the fingers 

 corresponding to the metacarpo-phalangeal and phalan- 

 geal joints, the highest is single for the index and 



